One idea could be exploring how Sasuke adjusts to the news. He might initially be shocked but then become extremely protective. Another could be Sakura dealing with her pregnancy while also handling her ninja duties in a more cautious way. For example, she might have to take on less dangerous missions.
A great plot could be centered around the reactions of their friends. Naruto might be overly excited and constantly checking in on Sakura. Kakashi could offer his wisdom on parenting. Also, the story could show how Sakura and Sasuke prepare for the arrival of their baby, like setting up a nursery in their home.
One idea could be that their child discovers a new, unique chakra ability. Since both Sasuke and Sakura are powerful ninjas, their genetic combination might lead to something extraordinary in their child. For example, the ability to combine Sakura's medical ninjutsu with Sasuke's Sharingan - like being able to see the internal damage of an enemy through the Sharingan and heal it instantly with a new form of medical jutsu.
A possible plot is that the child is born with a unique power that neither Sasuke nor Sakura have. This power could attract the wrong kind of attention, and the child has to learn to control it while also hiding it from those who would misuse it. The story could also involve the child making friends with kids from different ninja clans and trying to bridge the gaps between the clans, just like their parents did in a way. Also, the child might have to deal with the pressure of being the heir to two very powerful ninja legacies.
One plot idea could be that Sasuke is away on a mission when he finds out Sakura is pregnant. He then rushes back home, full of a mix of excitement and worry. Along the way, he has flashbacks of their relationship and how they got to this point. Another idea is that Sakura discovers she's pregnant during a time of unrest in the village. She has to deal with not only the physical changes but also the fear of what the future holds for her and her unborn child while Sasuke is off protecting the village.
Well, a possible plot is that Sasuke discovers a conspiracy against Sakura's pregnancy. Some mysterious group might be planning to use her unborn child for some dark purpose. So, Sasuke has to use his skills and intelligence to uncover the conspiracy and protect his family. Or perhaps, Sasuke has to deal with the internal politics of their village while protecting Sakura. The village elders might have different opinions on Sakura's pregnancy and Sasuke has to stand up for his family.
One idea could be exploring how Sasuke and Sakura adjust to the impending parenthood while also dealing with their ninja duties. Maybe Sasuke is away on a mission and Sakura has to handle the pregnancy alone for a while, which makes her stronger and more independent.
One idea could be that Sasuke and Sakura are in the same college but in different majors. Sasuke is in a more solitary, academic major like theoretical physics, while Sakura is in pre - med. They meet in a general education class and initially clash because of their different personalities. But as they get paired for a group project, they start to understand each other more. Another plot could be that they are both part of a college sports team, say a martial arts club, and they compete for the top position in the club, which leads to a lot of tension and also a budding romance. A third idea is that they are in a college that has a mystery or a curse. Sasuke, with his natural inquisitiveness, and Sakura, with her determination, team up to solve the mystery, and during this process, their relationship deepens.
One idea could be that Sasuke and Sakura are paired for a school project. They start off bickering but gradually learn to understand each other better. Another could be a school festival where Sasuke shows a hidden talent and Sakura is surprised. Maybe there's also a plot where a new student arrives and tries to come between them, creating some drama at school.
One idea could be a chibi adventure where Sasuke and Sakura are on a quest to find a rare flower that has healing properties. They encounter various cute and friendly creatures along the way that help or hinder them.
One plot idea could be that Sasuke, as a vampire, is initially conflicted about his feelings for Sakura. He might resist his attraction to her because he doesn't want to bring her into his dangerous vampire world. Another idea is that Sakura discovers Sasuke's vampire nature and tries to find a way to cure him, while Sasuke doesn't want to be cured as he sees his vampirism as part of his power. A third idea could be that there is a vampire clan war and Sasuke has to protect Sakura from the other vampires who see her as a weakness of Sasuke's.
Well, perhaps in the fanfiction, Sakura is a mermaid princess and Sasuke is a warrior from a nearby underwater kingdom. They meet during a battle between their kingdoms. Instead of fighting each other, they are intrigued by one another. Sakura's beauty and kindness make Sasuke question his loyalty to his own kingdom, and they start a secret relationship while trying to end the war between their people.